Electrical Conduction in Thoria and Thoriamdash;Yttria as a Function of Oxygen Pressure

摘要

The electrical conductivity of ``pure'' ThO2and some ThO2sngbnd;YO1.5solid solutions has been measured at 1000deg;C under partial O2pressures ranging from 1 to 10minus;14.6atm. For all specimens the conductivity is well described by sgr;=sgr;1+sgr;2pO2frac14;. The term sgr;1is interpreted as an oxygen ion vacancy conductivity which is fixed by the cation composition of the sample. The term sgr;2pO2frac14;is interpreted as a positive hole conductivity arising from the incorporation of excess oxygen into lattice vacancies via the reaction12O2plus;vO2minus;rlhar2;O2minus;plus;2h,wherevO2minus;is an oxygen ion vacancy, O2minus;is an oxygen ion, andhis a hole.